Copying Y scale value onto multiple objects
Here is a script (I don't know if there is another option) for now


copy and paste the script in the blender text editor 
select the objects
the object with the right scale should the active object (yellow outline , others red )
in the text editor click Run Script




import bpy

s= bpy.context.object.scale[1]
for obj in bpy.context.selected_objects :
    obj.scale[1] = s